Spinal stenosis of the lumbar and cervical spine is a common pain condition frequently found in the elderly. (Fritz, Delitto, Welch, & Erhard, 1998) Some of the symptoms of spinal stenosis include neurogenic claudication, extremity weakness, and radiculopathy. Patients predisposed to spinal stenosis include those who were born with congenitally shortened vertebral pedicles or those who have suffered excessive spondylosis of the spine secondary to degenerative disc disease. Spinal stenosis can occur at multiple spinal levels and multiple locations within a particular level including lateral recess, central canal, and intervertebral foraminal stenosis. As the spondylosis increases causing more pressure on the spinal cord or spinal nerves the symptoms progress.
Treatment of spinal stenosis includes administration of analgesics, epidural injections of local anesthetics with corticosteroids and decompression laminectomy. (Costandi, Chopko, Mekhail, Dews, & Mekhail, 2015) Decompression laminectomy is the preferred surgical procedure but includes risks of worsening the pain and nerve or spinal cord injury.
Decalcification of bone by citric acid/formic acid mixtures at low pH is a well-known histologic technique, but decalcification of bone exclusively with citrate under physiologic conditions of pH, tonicity and temperature has not been reported. (Seifter & Lavine, 1961; Vega, Narda, & Ferretti, 2003) Citrate can chelate calcium from calcium phosphate and calcium hydroxyapatite, the two major components of cortical bone. The rate of the reaction can be observed over days and definitely within a week.
Epidural injection for relief of various types of spinal pain including stenosis of the spinal cord, intervertebral foramina and lateral recess is a common low risk procedure performed by many pain practitioners. There are two main methods to perform the injection either transforaminal or translaminar. (Andreisek et al., 2013) Transforaminal injection is felt to especially target the anterior lumbar epidural space. (Manchikanti et al., 2015)
Infusion of substances into the epidural space with implantation of an epidural catheter is a common therapy that provides long term pain relief. Common medications for infusion include opioids, local anesthetics, clonidine and baclofen. (Jones, Anthony, Torda, & Poulos, 1988; Krishnamoorthy, Ravi, & Ganesan, 2015) Catheters with an infusion device can be implanted for years or catheters with an external port are frequently implanted in a patient for one week. Typical infusion rates are 5-15 ml per hour. Some complications of long term implantation of an epidural catheter include migration, bleeding, infection and granuloma formation.
In this invention continuous infusion of citrate via an epidural catheter will resorb bone that is contiguous to the epidural space and alleviate some of the symptoms of spinal stenosis.